Apparatus and method for determining the scuff resistance of leather



Jan. 11, 1949. c. w. MANN APPARATUS AND METHOD FOR DETERMINING THE SCUFF RESISTANCE OF LEATHER 3 Sheets-Sheet I Filed Feb. 24, 1947 .INVENTOR. GAMMANN 7Q 91- gm .1 r. 1W

ATTORNEY Jan. 11, 1 949; cyw. MANN APPARATUS AND: METHOD FOR DETERMINING- THE. S'CUFF RESISTANCE OF LEATHER 3 Sheets-Sheet 2 Filed Feb 24. 1947 INVENTOR. C.W.MANN v BY %7 7 $014 ATTORNEY Jan. 11, 1949. 2,458,953

' C. W. M N APPARATUS AND METHOD FOR DETERMINING THE SCUFF RESISTANCE OF LEATHER Filed Feb. 24, 1947 5 Sheets-Sheet 5 INVENTOR. cmmun ATTORNEY Patented Jan. 1 1, 1949 APPARATUS AND METHOD FOR neme- MINING THE SCUFF RESISTANCE OF LEATHER Charles W. Mann, Silver Spring, Md., assignor to the United States of America as represented by the Secretary of Agriculture Application February 24, 1947, Serial o. 730,578

' '10 Claims. (cite-7) (Granted under "the act of March 3, 1883,

.3, 1883, as amended by the act of April 30, 1928,

and the invention herein described, if patented, may be manufactured and used by or. for the Government of the United States of America. for overnmental purposes without the payment to me of any royalty thereon.

This invention relates to an apparatus and a method for determining physical characteristics of leather and like materials. It isparticularly directed to expeditious determination of the scuff resistance of leather.

In its preferred form the apparatus comprises a specimen holder mounted for rotation about a horizontal axis, a weighted pendulum mounted for independent rotation about the same axis, a smiling or abrading tool mounted upon the pendulum or upon an arm fixedly attached to the pendulum, adjusting and measuring means to set the radial overlap between the surface of the specimen and the edge of the scufling tool to produce the desired depth of scuff, operating means to turn the specimen holder at a slow constant angular velocity, and a force indicating scale and a pointer operated by the deflection of the pendulum weight from its lowest point as the tool scuffs through the leather overlap.

In the drawings:

Figure 1 is a face view of the apparatus, with crankshaft and gears removed;

Figure 2 is a view of the specimen holder;

Figure 3 is a front view of the specimen holder of Figure 2;

Figure 4 is a face view of the apparatus showing the hand crank and gears in place, other parts bein removed;

Figure 5 is a cross-sectional view;

Figure 6 is a view of the specimenclampj Figure '7 is a top view of the scufling tool;

Figure 8 is a view of the support arm for the scufiing tool.

Figure 9 is a top view of the pivoted supporting block for the specimen supporting arm.

The apparatus comprises a casing I containing an electric motor-operated shaft 2 (Fig, 5) and reduction gear 3, which gear turns shaft 4 at slow constant speed, for example, at 0.2 R. P. M. The shaft may also be operated by handcrank 5 through worm rod 6 and gear 1 in casing 1'. The gear 1 is welded or otherwise rigidly attached to block 8 (Fig. 5). Block 8 is rigidly connected to flange plate 9, fixed upon the end of the shaft 4.

Block 8 has a slot at In in which the extension bar II is supported. Bar ll isgrooved at [3, in which groove is held a flange I4, rigidly attached to micrometer caliper head I5. The outer, face of the flange l4 projects'above the corresponding face of the bar II, the groove depth being less amended April 30, 1928;3{70 0. '757) 2 than that of flange. Set screw 12 therefore fastens both extension bar i l and flange M in place in slot Ill. Micrometer head l5 supports the spindle I 6 which is adjustable in position by turning rotatable piece I1. Stock parts of a standard inside micrometer caliper may be used, such as those of Brown and Sharpe Manufacturing Company,No. 250. Spindle l6 moves longitudinally in the head l5, but does not rotate, preferably. Scales l6 and I1 on IS and I 1 are provided for accurate determination of the position of the leather specimen.

Rigidly attached to the other end of the spindle I6 is a specimensupport l8 having a curved end of roughly semi-cylindricalfshape. As shown in Figure 3, the curvedend is provided with a projection l9 extending transversely to the axis of the spindle, and parallelto the shaft 4 when as-. sembled. The purpose of this projection is to cause the surface of the specimen to impact the blade at such an angle as to produce a scufling cut. The leather'specimen 20 is held in position by spring clamp 21 which has a curved portion to fit on the curvedend of the specimen support l8. The curved portion is cut out at 22 to expose a portion of the leather specimen; As shown in Figure 6 one edge of the cut-out'portion'or' aperture is provided with slightly depressed projecting tongue 23. When assembled the tongue is preferably a short distance below the projection l9, inFigure 1.

The pendulum 21-29 turns independently of, but coaxially with, the specimen support arm.

' The rotating shaft 4 carries the work or specimen support arm, comprising'elements ll, [5, I 6, l1, and so forth. Shaft 4 is supported in a fixed bushing 24 which is attached to and supported in an opening in wall 25 (Fig, 5). Mounted on bushing 24, :by means of ball bearings 25, is a hollow spindle 26. To the spindle is attached a pendulum disc 21, which is provided with one or more projecting'pins 28 serving as supports for one or'more removable weights 29. Attached to the upper part of the disc 21 is a, pointer 30 which moves over scale 30'; A

The tool support consists of a bracket arm 3| rigidly fixedupon disc 21 by means of screw.32 and pin 33. Flange 34, on arm 3 l, extends forward from the face of the disc, at a right angle thereto. Scufiing tool 35 is mounted upon flange 34 by tightening one or more screws 36 in slot 31. The knife is therefore adjustable in position in a direction parallel to the shaft 4. The edge 38 is sharpened and is of standardized width, one thirty-second of an inch, for example.

When the apparatusis assembled the specimen support and the scuffing blade .lie in the same plane of rotation and the distance betweenthe' support until it faces the scuffingblade.

specimen support and the tip of theqscufling blade can be regulated by using the micrometer mechanism to move the specimen support radially of its axis of rotation. i

The operation of the apparatusis asfollowsz A piece of leather to be tested is placed over the free end of the specimen support and fastened firmly in position with the clamp.

The crank is then used to" rotatethe specimen means of the micrometer mechanism the specimen support is then positioned so thatthe tip'of the blade nearly touches the specimen, the crank being turned until the distance between specimen and blade is at the minimum. The .micrometer is then set so that the blade just touches the surface of the leather. ';The specimen support is then turned counter-clockwise to lift it out of alignment with the blade. The micrometer mechanism is then adjusted to produce the desired d pth of scuff, for example, 0.0 0 to 0.025 inch. The specimen support is then rotated clockwise by means of the motor drive at a constant speed of about 0.2 R. P. thereby bringing the outer portion of the specimen in contact with the tip of the scufling blade and causing deflection of the pendulum system. The scufi resistance of the leather is indicated by the maximum load registered by the pointer before the blade scufis through the specimen, and the pendulum system :1

the weight used as the bob. of the pendulum and can .be varied by using a series of detachable weights. .The force bearing upon the specimen through the scuffing bladeis also a function of 4 3. The apparatus defined in claim 2 in which the fastening means for-the scuiiing tool is adjustable to permit adjustment of the position of the tool longitudinally to the axis of the pendulum.

4. The apparatus of claim 2 in which the operating means includes power-driven means for turning the material holder at constant angular velocity. 3

5. The apparatus of claim 2 in which the work arm includes a head, a movable spindle supported at one end by the head, a specimen support attached to the other end of the spindle, means to move the spindle transversely to the axis of rotation of thework arm, and length measuring indicia on the spindle.

6. The apparatus of claim 5 in which the head is provided with a rigidly affixed flange, means for removably attaching this flange to the axis of the pivoted holder.

F7. The apparatus .of claim -1 in which the specimen holder means and the. tool support are coaxially pivoted, and the specimen support is providedwith an arcuate end, the means for fastening the specimen material comprising a clamp having an apertured arcuate portion fitting upon the said arcuate end.

8,. The apparatus of claim '.7 in which th arcuate end of the specimensu'pport is provided with a peripheral projection extending longitudinally to the axis 01f rotation of the Work arm.

9. "A method of indicating the force required to scuff material, comprising mounting the material for rotation about a horizontal axis, mounting a scuffing tool for independent rotation about the same axis, setting theradial overlap between the surface of the material and'the cuttin edge the distance between the axis of rotation of the specimen holder and the tip of the scuffing blade; The weights attached to. the pendulum may be calibrated in inch-pounds.

Having thus described my invention, I claim: 1. An apparatus for determining the scuff recombination of the tool, weighting the tool, turning the material about the horizontal axis at a slow speed which minimizes the efiect of impact, causing the turning surface of the material to engage and turn the weightedscufiingtool about its horizontal pivot, and determining the force required to scuff through the preset depth of leather by indicating the maximum deflection of the weighted scufling tool. y

10. In an apparatus for determining the scuff resistance of material such as leather, the subcomprising a specimen holder mounted for rotation about a horizontal axis, a

Q Weighted pendulum mounted for independent rosistance of material such as leather, comprising a scuiiing-tool support means including a pen dulum, means for fastenin .the scufiing tool to the pendulum; specimen-holder means for the material being tested, which holder ismounted for independentrotation about an axis parallel to that of the pendulum, thespecimen-holder means-including a work arm carrying a specimen support, means for fastening the material on the specimen support, and means for moving the pecimen support transversely to the axis of retation of the specimen holder to adjust the radial distance between the surface of the material and the axis of rotation of the scufiingetool suppo and to pre-set the radial overlap between the surface of the material and the cutting ed e of the scufling tool; means for turning the specimen holder through an arc; and means for indicatin the displacement of the pendulum as the cutting tool scufis through the material.

2. The apparatus defined in claim .1 in which the supportemeans and the holder means ar co-axiallvpivoted.

tation about the same axis, a scufiing tool mounted by the pendulum, adjusting and measuring means to pre-set the radial overlap between the surface of the specimen material and the cuttingedge of the scuff ng tool to produce the desired depth of scuff.

CHARLES W. MANN.

REFERENCES orran The following references are of record in the file of this patent: V

UNITED STATES PATENTS 50,880 Great Britain July 2'7, 1936 

